Month: November 2014

Apple Mac OS X is a brilliant OS but unfortunately it’s missing a good image viewer. In comparison, Windows has Preview and Ubuntu has the Gnome Image Viewer both of which are great. I did some research and the image browser i found was Lyn Image Browser. I like it so much… I thought I would put write a little review for it.

So why is it so good?

1 – Great Thumbnail Viewer
Lyn Image Browser has a great thumbnail viewer where the images are large enough to actually see them. You can browse through folders really quickly and easily.

You can also view all the image information:

2 – You can flick between images
This might not sounds like much of feature but frankly it is. Apple’s Preview is missing this key feature and is super annoying while both Windows preview and Gnome image viewer both have this feature.

Finally… its fast and lightweight
I hate slow applications and this one is very fast and lightweight and doesn’t hog the cpu.

So, if you are looking for a image viewer for Mac OSX then I can highly recommend Lyn Image Browser.

Sometimes it can be really useful to give a user privileges to run a specific command as root. For example – if you wanted to allow a user to restart a specific service or run a specific program as root without given them access to the whole server. You can configure this using visudo command as root. Note: you really must be root when you do this and not a sudo.

sudo su -

Then..

visudo

You can then modify the configuration file. There are specific sections in the config file which are show below. For example – I want to give a user called debug permission to run supervisorctl as root.

I was trying to sftp some files using Python Paramiko on Ubuntu 14.04 and got the following error: “paramiko.SSHException: Incompatible ssh peer (no acceptable kex algorithm)”. It turns out that there is an incompatibility issue with OpenSSH 6.7 and Paramiko with a version less than 1.15.1. At the time of writing (November 2014) Ubuntu 14.04 came with 1.10.1.

To fix the issue, you need to upgrade Paramiko to at least 1.15.1. You can do this by using PIP which is a Python package management system. Here is how to you do this:

I have a few Synology NAS at work which are used for storage. I have been locking down the firewall on them to only allow certain ports from specific IP subnets. However, I still wanted to be able to ping the Synology from anywhere. I couldn’t work out how to configure the Synology firewall to let through pings ( ICMP messages).

You have to go to: Control Panel -> Security -> Firewall -> Create:

Under ports select Custom and then under protocol select ICMP.

Press OK a few time and then Save the firewall settings. You should then be able to ping the NAS without any problems.

I wanted to monitor the bandwidth usage on my Ubuntu server without a full blown graphic monitoring system but something that I could just check once in a while just to see how things are running. I found an really simple tool called vnstat. It’s good because it’s simple, fast and easy to use and that doesn’t require a PhD in networking to get going. It also nicely presents the data with good summaries.

Here is how I setup network traffic monitoring using vmstat:

1 – Install vnstat – note there is another program called vmstat – so be careful what you type.

sudo apt-get install vnstat

2 – Configure the network adapter to monitor. Vnstat automatically configures the network adapters however it’s worth checking that they are correct and having a quick peek through the configuration file.

sudo nano /etc/vnstat.conf

If you do have made any change then don’t forget to restart the service.

sudo service vnstat restart

3 – Get you first report – You will have to wait a few minutes to get your first report. This how a typical report looks like:

I use source control while developing software. Apple’s OSX creates .DS_Stores files in any folder that you browse with Finder. These are normally hidden but they obviously aren’t ignored by version control which is designed track everything including hidden files. I could add them to the .ignore files in both Mercurial or Git – but this is time consuming and annoying.

Therefore, I installed asepsis which an lightweight opensource tool. This forces Mac to store all the .DS_store files in another location. It was quite straight forward to get going.

1. Download the software
2. Install it
3. Restart the computer
4. Migrate all the existing DS_store files using the command:

I’ve moved from Ubuntu to Apple Mac OSX and like to use Firefox. However, rather annoyingly the Firefox spell checker doesn’t appear to work on Apple by default. Bizarrely, it doesn’t highlight any incorrect spellings. I found that the only way to fix it was to add another dictionary to Firefox. Here is how I did it.

Step 1 – Find a dialogue box or text box and right click. You should see a menu like so. You could click Language -> Add Dictionaries